Draw cushion for die presses



, Mar. 3, 1925.

1,528,365 5. BROWN I DRAW CUSHION FOR DIE PRESSES Filed Noy. 28, 1923 ai' P J 77/ iI' I na (Mtg.

Patented Mar. 3, 1925.

UNITED STATES PATENT OFFICE.

STEWART BROWN, or cHrcAeo, r'pnmors.

DRAW CUSHION FOR DIE PRESSES.

Application filed November. 28,1923. Serial No. 677,582.

To all whom it may concern Be it known that I, STEWART BROWN, a

' citizen of the United States, anda resident panying and forming a part hereof, is a I specification.

pressure to a desired one.

This invention relates to a cushion which is to be used in a die press when sheet metal is to be drawn into a determined shape by dies installed in said press.

Among the objects of'the invention are to obtain a draw cushion which can be regulated to obtain the pressure desired on the metal which is being drawn into shape by the dies in the press, and to obtain a draw cushion wherein the pressureon said sheet metal will be maintained in the successive movements of the die press. 'A further obiect is to obtain a draw cushion the pressure whereof is easily changed from a given A further object is to obtain a draw cushion which is durable, not liable to break or get out. of

order, anda draw cushion which is economi cally constructed, and easily adjusted.

In the drawing referred to I have illus trated a draw cushion embodying the invention in vertical section.

A reference character applied to designate a given part indicates said part throughout the figure of the drawing.

A represents the bed of a die press, and a an aperture in said bed'which is substantially concentric with-the dies in the press. B represents the lower end of the movable one of drawing dies of a press, and C represents the immovable or stationary die. D represents the die shoe or base of die 0. Said base rests on the bed A of-the press, over aperture a in said bed. E represents a receptacle which is closed at the upper end thereof by head 6, and at the lowerend by head 6. The receptacle E may be a cylinder, and it is held rigidly in place by bolts F, F, disk 7, and bolt G; the bolts F, F, being screw threaded and secured at their lower ends in head e, and at their upper ends in disk 7, said screw threads respectively engaging with corresponding screw threads in apertures provided therefor in said head,

and disk. The bolt G is screw threaded at both ends, and the lower end secured in disk' f, and the upper end extending through die shoe D and secured in die 0.. H represents a check valve, which may be of the kind usually employed on the inner tube of automobile tires, to permit the forcing of air thcrethrough in one direction and prevent its escape through said valve in the opposite direction; and by means ofsaid .check valve H air may be forced into receptacle E. I is a line indicating the normal height of water or other liquid, as 'oil, in receptacle E. J represents a eylinderwhich is rigidly mounted in receptacle E, by means of internal screw threads j in the upper end thereof, which engage'with cor-responding screw threads on flange K of head 6. L represents a disk which forms a valve when seated, as illustrated in the drawing, closing the lower end of cylinder J. I represents an aperture in disk L. M represents a spring which yieldingly holds disk L seated on said lower end of cylinder J. N represents a pin which is secured to the under side of disk L, and n represents an abutment on head e, which is provided with a recess or aperture in which the pin N is longitudinally movable. Said pin and abutbolt 7). Q represents a rod or bolt which is.

screw threaded at both ends, the lower end thereof secured by corresponding screw threads in head 0, and the upper end secured in disk R by corresponding screw threads in a central aperture. in said disk.

S, S, respectively represent bolts which are screw threaded at both ends, and which are secured at their lower ends in disk R by said screw threads engaging with corresponding screw threads in aperturesprovided therefor in said disk, and at their upper ends in pin ring 'I, by the screw threads on said upper ends engaging with. corresponding screw threads in apertures provided therefor in said pin ring. U, U, respectively represent pins or bolts which are screw.

threaded at both ends thereof, and V represents a draw ring. The lower-ends of pins U, U, are secured in the pin' ring T, by the screw threads thereon e aging with corresponding screw threads 1n apertures provided therefor in said pin ring; and the upper ends of said pins are secured in the draw ring V by the screw threads thereon engaging with corresponding screw threads in apertures provided therefor in said draw ring. The pin ring T is provided with a central aperture t, the walls whereof do notcome in contact with the bolt G, so that said pin ring may move up and down relative to said bolt. as required in the operation of the draw cushion. The disk f is also provided with apertures, f, f, through which the several bolts S. S, respectively extend, the walls of said apertures not being in contact with said bolts. so that said bolts may move freely longitudinally in said apertures.

The operation of the draw cushion is as follows: When. sheet metal is placed between the dies B and C, and said die B is forced downward to force said metal on to the draw ring V, further downward move- 'ment of said die B forces said draw ring downward, thereby forcing pins U, U, pin

ring T. bolts S, S, disk.R. bolt Q, and piston.

head 0 O, downward in cylinder J. Air having been forced into receptacle E, through check valve H, the liquid in receptacle E is put under pressure, and said liquid will flow through aperture Z in disk L into cylinder J, underneath piston head 0 O. and the same pressure will exist in said cylinder J below and on said piston head that exists in receptacle E. The forcing down of the piston head 0 O, by the foreing down of the draw ring V, as above described, creates a greater pressure in cylinder J than exists in receptacle E, and the disk L will be forced from its seat against the resilience of spring M. so that some of the liquid in cylinder J will flow therefrom,

between the lower end thereof and said disk L, into the receptacle E, thereby increasing the pressure in said receptacle E, to substantially equalize the pressure therein and in cylinder J. The relative quantity of liquid and air in the receptacle E will determine whether the increase in pressure produced by the above described operation is of slight or considerable amount. When the die B is moved upward the draw ring V is forced upward by the pressure of the liquid contained in cylinder J acting on piston O O, and the connecting bolt Q, disk R, bolts S, S, pin ring T and pins U, U. The disk L will be seated by spring M, when the pressure is substantially equalized in receptacle E and cylinder J; and upon any further upward movement of piston head 0 O a flow of liquid fromreceptacle E through aperture Z into cylinder J, until the pressure is equalized in said receptacle and cylinder, will follow.

The aperture Z is sufficiently large to obtain said equalization of pressure in .said

receptacle andcylinder before the following downward movement of the draw ring V causes a corresponding downward movement of piston head 0 0', but is not large enough to permit the sudden outward flow of liquid from cylinder J into receptacle E,.and hence, as above described, on said downward movement the disk L is forced downward to permit the flow of liquid from cylinder J between the lower end of said cylinder and said disk, into receptacle E.

The size of the restricted. opening, Z, determines the Velocity of the piston in its upward movement, and should be determined to limit said upward movement so not to exceed the upward movement of the upper die,(B) thus preventing pounding of the die press.

I claim:

1. In a draw cushion for die presses, a stationary receptacle adapted to contain liquid and air under pressure, a stationary cylinder open at its lower end mounted in said receptacle, and a diskyieldingly held in normal position in contact with said lower end, said disk provided with an aperture, a piston head movably mounted in said cylinder, in combination with a draw ring, and connections between said draw ring and said piston head to obtain corresponding move-' ment of said draw ring and said piston head, to force said head against the contents of said cylinder on the downward movement of said draw ring..

2. A receptacle provided with closed ends and adapted to contain liquid and air under pressure, means to suspend said receptacle, in combination with a stationary cylinder mounted in said receptacle, yielding means to substantially close the lower end of said cylinder, means to establish continuous restricted communication between said receptacle and said cvlinder, a piston head movable in said cylinder, a draw ring, connections between said piston head and said draw ring to obtain corresponding movement, and said draw ring arranged to be forced downward by the downward movement of a movable die.

3. A closed receptacle adapted to contain liquid and air under pressure, a disk, means to suspend said disk from a stationary die and means to suspend said receptacle from said disk. in combination with a stationary cylinder mounted in said receptacle, yielding means to substantially close the lower end of said cylinder, means'to establish continuous restricted communication between said receptacle and-said cylinder, a piston head movable in said cylinder, a draw ring, said piston head and said draw ring connected to obtain corresponding movement thereof,- and said draw rin arranged to be forced downward by the ownward movement of a movable die.

4. A closed receptacle adapted to contain liquid and means to force air under pressure bination with a stationary cylinder open at into said receptacle and to retain air in sald receptacle under pressure, a cylinder suspended in said receptacle, yieldi'ngmeans to substantially close. the lower end of said cylinder and means to obtain continuous restricted communication between said receptacle and said cylinder, in combination with a movable piston head in said cylinder, a

draw ring, and means to connect said piston head and said draw ring to obtain corresponding movement, and said draw ring arranged to be forced downward by the downward movement of a movable die.

5. A stationary receptacle adapted to con-. 7

tain liquid and air, under pressure, in comg its lower end, mounted in said receptacle, a piston movably means com rising a yieldingly mounted closure to sai open end of said stationary cylinder, to permit the flow of liquid from said cylinder to said receptacle on the downward movement of said piston, and means comprising a restricted aperture to control the volume of flow of liquid from said receptacle to said cylinder on the upward move ment of said piston,

STEWART BROWN.

Witnesses:

' CHARLEsTURnER BROWN,

Bass BROWN.

mounted in said cylinder, 

